title: Sequential fluoroimmunoassay for measurement of pregnancy specific beta 1 glycoprotein using antibody coupled to magnetisable particles.
abstract: A direct, sequential fluoroimmunoassay has been developed for the determination of serum levels of pregnancy specific beta 1 glycoprotein (SP1). The method employs rabbit anti-SP1 serum coupled to magnetisable cellulose-iron oxide particles and fluorescein-labelled SP1. Serum samples or standards are incubated with magnetisable solid phase anti-SP1 for 30 min. After magnetic sedimentation of the particles, the supernate, which includes endogenous fluorophores and other interfering factors, is discarded. Fluorescein-labelled SP1 is then added and incubated for a further 45 min; the particles are again sedimented and the fluorescence of the labelled SP1 remaining in the supernate is estimated. This reading related directly to the SP1 content of the original sample. The entire procedure, including fluorometry, is performed within a single disposable polystyrene test tube and is sufficiently simple and reliable for routine application. The sensitivity, specificity and precision is very similar to that of radioimmunoassay, and the results correlate with those of the radioimmunoassay (r = 0.9887).
mesh_terms: D005260:Female; D005290:Ferric Compounds; D016650:Fluorescein-5-isothiocyanate; D005452:Fluoresceins; D005455:Fluorescent Antibody Technique; D006801:Humans; D007106:Immune Sera; D008280:Magnetics; D011247:Pregnancy; D011257:Pregnancy Proteins / Q000032:analysis*; D011268:Pregnancy-Specific beta 1-Glycoproteins / Q000032:analysis*; D011863:Radioimmunoassay / Q000379:methods; D013861:Thiocyanates
chemical_list: D005290:Ferric Compounds; D005452:Fluoresceins; D007106:Immune Sera; D011257:Pregnancy Proteins; D011268:Pregnancy-Specific beta 1-Glycoproteins; D013861:Thiocyanates; C000499:ferric oxide; D016650:Fluorescein-5-isothiocyanate